XENOPROBE

Introduction

XENOPROBE is our name for our line of streptavidin coated products. Our products are different from most of the other streptavidin products currently available because the streptavidin is covalently attached to the surface.The covalent attachment is achieved by a proprietary attachment chemistry which binds the streptavidin without affecting its biotin binding properties.

Covalent attachment provides exceptional uniformity and stability. AFM studies have shown that the streptavidin is primarily present as a monolayer, with few uncoated spots and few multilayer attachment points. There are approximately 10 exp(13) biotin binding sites per square centimeter, although steric hinderence limits the number of biotin labeled molecules that can be attached.

Plates and Strip Plates

The XENOROBE products are available in standard 96 well plate format and as strip plates, which have 12 strips of 8 wells in a frame in the standard 8 x 12 format. While more expensive than solid plates, the advantage of this format is that you can use as few or as many wells as needed in any given assay without the possibility of contamination of the other wells by spillage.

The plates and strips are available in clear polystyrene for colorimetric ELISA assays and in opaque white or black for chemiluminecent and fluorescent assays.& These assays have the advantage of being much more sensitive than colorimetric assays and they can also be used for direct imaging when no enzyme reaction is involved.

We also have streptavidin coated microscope slides and cover slips that are described on a separate page.

Suggested Protocol

Before beginning an assay, the wells must be rehydrated. Fill each well with a neutral pH buffer such as PBS. Allow to stand for 10 minutes. Empty the wells and repeat twice more. The wells are now ready to use.

1. Prepare a solution of the biotinylated capture antibody at a concentration of 3 – 5 ug/ml in a neutral pH buffer.

2. Incubate in the wells for 1 hour at room temperature or 37 degrees.

3. Wash three times with the same buffer.

4. Block with a freshly prepared 1% solution of BSA in water or PBS. A solution more than a few hours old contains dimers and trimers which are not effective in blocking.

5. Incubate for 1 hour at room temperature.

6. Wash three times withe same buffer.

7. Incubate with the antigen solution for 1 hour

8. Wash three times.

9. Incubate for 1 hour with the detection antibody.

10. Wash three times.

11. Incubate with the enzyme substrate. The time depends on the speed of the reaction, but should be standardized for quantitative results.